Locomotives are required by law to be inspected once every ninety-two days. During an inspection, failure to detect degrading components in a locomotive's electrical cranking system may result in a failure in the following ninety-two day period. A defect in a locomotive cranking system requires additional labor at the railroad's maintenance facility. If a failure in the energy storage unit or energy storage unit cabling occurs on a railroad track during a mission while pulling rail cars, such failure can stop rail traffic on a set of tracks until the locomotive is serviced. Each mission failure is estimated to cost a railroad in excess of ten thousand US dollars.